16.1 - Project Proposal - Team 16
Introduction:
Automated pick-and-place systems are widely used in industries such as manufacturing and e-commerce for tasks that require speed, precision, and repeatability. Designing a compact and reliable mechanism to perform these motions provides valuable experience in robotic motion control and mechanical coordination. This project aims to replicate the fundamental functions of an industrial manipulator, grasping, lifting, and placing objects, through a simplified mechanism that emphasizes safe and efficient motion design. To simulate real world automation, we will include a conveyor mechanism to feed parts to the arm and sensors to detect the presence of objects.
Description of the problem:
The system must execute repeatable pick‑and‑place motions with Z‑axis approaches and retreats at both pick and place to prevent lateral contact, ensuring safe operation around fixtures and neighboring items. It must maintain commanded pose through transport and cover the drop location without reconfiguring the layout. Real world applications could include item picking and sorting in the case of e-commerce order fulfillment or picking and moving heavy items to a desired location perhaps off of a conveyor belt.
Proposed Mechanism:
Use a rotating base to swing the arm between the pick spot and drop zones; it’s a simple way to cover the workspace reliably.
The arm itself is a four bar mechanism which would allow for Z travel so the gripper moves down to grab and straight up to clear parts, reducing collisions with the object
Choose a basic gripper: parallel-jaw for general shapes, or suction for flat, smooth parts—pick based on the object surface and geometry.
Run a simple cycle: rotate to pick, go down, close, lift, rotate to place, go down, open, and back away for repeatable operation.
A small conveyor belt will feed items into the pickup zone and sensors will detect when an item arrives which will trigger the cycle mentioned above. In the drop off zone, more sensors can be used to choose the appropriate bin.
Scope of work:
Our goal for this project is to have a functional actuated rotating base, 4-bar linkage, and gripping end-effector. A conveyor infeed of the product will be “simulated” by placing small boxes for the gripper to collect. Then, these boxes can be “sorted” into their individual boxes by having a human operator click a button to designate each box.
Additionally, a small conveyor system will be designed to feed objects into the pickup zone. Proximity sensors such as infrared or ultrasonic will detect when an object arrives at the pickup location and will trigger the arm to pick up and place the objects. Also, sensors at the drop locations can be used to assist with sorting.
High-level geometry like the robot, conveyor, and sorting box layout will need to be set along with critical geometry such as the product dimensions, gripper style, and 4-bar linkage. Following the geometric definition, kinematic analysis will be performed to verify the linkage motion, workspace coverage, and avoidance of singular positions. CAD modeling and motion simulation will then be used to confirm the designed mechanism achieves the desired pick-and-place motion with smooth Z-axis translation. After verification, the components will be fabricated using 3D printing and off-the-shelf hardware for assembly and testing.
The main goal by the end of the semester is to demonstrate a fully functional mechanism capable of executing repeatable pick-and-place operations under simple human input. If additional time allows, the project could be extended by incorporating sensors or automation logic to enable autonomous sorting based on object type or color. This progression would connect the mechanical design with broader applications in robotic automation and industrial sorting systems.
Our goal for this project is to have a functional actuated rotating base, 4-bar linkage, and gripping end-effector. A conveyor infeed of the product will be “simulated” by placing small boxes for the gripper to collect. Then, these boxes can be “sorted” into their individual boxes by having a human operator click a button to designate each box.
Preliminary Design Ideas:
The mechanism will use a 4-bar linkage on a rotating base. The base rotation covers movement between different zones, while the arm provides vertical movement to lift boxes.
The overall robotic arm is designed with four degrees of freedom (DOF): a rotating base (waist), shoulder joint, elbow joint, and wrist rotation. These four joints provide the arm with the ability to move horizontally, reach vertically, and orient the gripper properly to pick and place objects. This level of motion is enough to control both the position and orientation of the end-effector within the robot’s workspace.
Within the arm, the Z-axis motion is generated by a four-bar linkage. While the complete robot has 4 DOF in total, the four-bar linkage itself is a single-degree-of-freedom planar mechanism. This means one actuator controls the entire linkage motion, and all link positions are dependent on that single input. The linkage was chosen because it produces a smooth, constrained up-and-down motion at the gripper, reducing lateral movement and improving stability when grabbing parts.
The gripper mechanism will use a small servo to actuate the gripping movement. A conveyor will feed small boxes and the infrared sensors will detect when a box arrives and sets off the pick and sort cycle.
The four bars will be modeled as: M=3(N-1)-2J=1. Continuous motion will be ensured by satisfying the Grashoff condition : S+L< P+Q.
The robot system achieves 4 DOF for flexible pick-and-place operation, while the four-bar linkage subsystem provides 1 DOF of controlled Z-axis motion .
Layout
Diagram
End effector motion profile